Hi all. If I understand correctly, there is no way in Tableau to use a calculated field as part of a join. So, if I use a substring expression to create a new column with term name (say, Fall2015) from a column that is in my original data source (where the original value is, say, "Fall2015FullTimeFirstTime"), that new column then doesn't appear in my list of fields on which I can join.

To get around this, I would need to create the new column in Excel first, so that Tableau recognizes the column as part of the original dataset.

If you expand the list to see the columns available for join, right at the bottom there is an option to "Create Join Calculation". You can copy your formula and include it in this and use in the join as required.

Ok, this does seem to work. I can write the substring expression into the join calculation itself to achieve the desired result. Thanks for this solution. I'll still maintain that it would be a lot easier to be able to reference the column itself. That's how other reporting tools typically work in my experience.

I understand your concern. You could create an idea if it's not already there and get people to vote on it so that Tableau may act on it. But, for now, it's better to have a solution than no solution at all.

I must say this is a misleading - or at least misstated feature addition: if Tableau claims the ability to create joins on calculated fields has been added, why is the procedure so convoluted as to require copying the contents of the calculated field into a join clause...? Why can't it simply be a field to select, along with native fields? Again, that is the stated product feature...

This is my feeling. I would expect to click the drop-down list of fields and see whichever ones I've created. Other reporting solutions, like Hyperion, allow for joins on calculated fields in this way.

I see what you mean, Hari: the distinction seems to be between allowing a join on a calculated field vs a calculation. I now notice that subtle distinction in the official help article on the subject procedure. Your reminder that calculated fields exist only in the workbook - and not in the data source - made it clear to me...thanks.